Linksys RE6500 2.4Ghz stops transmitting

Hi All,
I have Linksys RE6500 Access Point installed with OpenWrt 21.02.1.
I encounter a problem that randomly the 2.4Ghz SSIDs disappear and all the clients are disconnecting.
It has a MediaTek MT76x2E radio, and originally I had 4 SSIDs on it, due to the issue I deleted one, and disabled another one (so now there are only 2 active SSIDs), and still I encounter the issue. There are around 10 Associated Stations.
When it stops working, the 5Ghz SSID is still transmitting and working properly.
Resetting the MT76x2E radio solves the issue for some time, and then it returns...
I see nothing in the kernel or system logs from the time of the disconnections (some clients log the exact disconnection time).

Anyone has any idea what can cause this problem? Can it be because there are more than 1 SSID on the radio?